Pre-sterilized, disposable medical products are commonplace in the United States, and other countries throughout the world. One significant restraint on the design, development, and manufacture of such products has been the fact that certain desirable products would include portions or components which are mutually incompatible from a sterilization standpoint. For example, it may be desirable to provide a unitary, pre-sterilized product which has a sealed liquid or powder drug component and a plastic apparatus component, such as a tubing or flow control set.
The integral product, however, cannot be sterilized after assembly because not all of the components may be subjected to the same form of sterilization. That is, the plastic apparatus component (e.g., the tubing or flow control device) may only be capable of sterilization with radiation or gas. The drug component, on the other hand, may not be sterilized with either gas or radiation—gas sterilization would be ineffective to sterilize a sealed drug, while exposing the drug to radiation may lead to product degradation or otherwise have a deleterious effect on the drug.
Accordingly, efforts have been made to devise a method or means for joining, in a sterile manner, components which are individually pre-sterilized. Such efforts have included the use of electron beam accelerators to sterilize the compromised portion of the assembled components. Electron beam sterilization is a well-known and accepted technique for terminally sterilizing disposable medical devices. Existing electron beam systems are high voltage devices whose electrons completely penetrate the materials being sterilized. Such a device and method is disclosed in U.S. Pat. Nos. 5,009,654 and 5,496,302, both to Minshall et al., and both assigned to Baxter International Inc.
The electron beam used in Minshall et al. is derived from a high energy (>0.3 MeV or 300 KeV) instrument to “achieve sterilization at the tubing center.” Energy levels of 1.1 MeV, 0.9 MeV, 0.75 MeV, and 0.6 MeV are disclosed for sterilization. The high energy process involves clamping the tubing to be connected together close to their terminal ends. Then the terminal ends are cutoff and the open ended tubings are bonded or welded together. Before the new fluid pathway is opened, the high energy electron beam is applied between the two clamps to effect sterilization. While these type of high energy systems function well, when compared to the present invention they can be considered very large (sometimes requiring a separate room with thick walls of lead shielding), more expensive, and somewhat product-specific.
Another example of creating a sterile connection is disclosed in U.S. Pat. No. 4,157,723 and Reissue No. 32,056 to Granzow et al., each assigned to assignee of the present invention. The Granzow et al. invention is based upon a clear TPX unisex connector housing containing an integral black TPX (carbon doped) disk. The connectors are attached to tubing from, for example, a solution container that has been steam sterilized, which is connected to similar tubing from a solution delivery set which has been ethylene oxide (EtO) or Gamma sterilized. Snapping two connectors together and applying an intense focused light beam on the black disks quickly melts them together to form an annular ring that completes the sterile fluid path and effects a sterile connection. Subsequent to connection, the solutions would be transferred to empty solution containers, while the sterile connectors, including the original solution containers, were removed and discarded. Although functional, the present invention provides a method which improves the rate and cost of this process.
E.I. Du Pont developed and patented a “Hot Knife” tubing to tubing connection system, as shown in U.S. Pat. No. 4,521,263 to Benin et al. In this system, two thermoplastic tubes with sealed ends facing each other are placed side by side in a fixture incorporating a special heated knife blade. A connection is made by (1) cutting through both tubes with the heated knife blade, (2) shuttling the tubes to be connected into alignment on each side of the heated knife blade, and (3) removing the heated knife blade while pushing the tubes together. This system can be more expensive to use than the present invention because it requires the use of a new disposable knife blade for each connection made.
The apparatus and methods of the present invention overcome the disadvantages of other prior art techniques. The present invention is focused on maintaining the sterility of the pre-sterilized components during assembly, connection, and fill, rather than attempting to effect sterilization after such manipulations, like the processes used extensively by those skilled in the art. Additionally, the present invention is focused on processes which are far less expensive than techniques utilizing disposable parts.